On Tue, 9 Oct 2012 19:24:38 +0100
Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Now that we seem to have brought order to the GTT barriers, the last one
> to review is the terminal barrier before we unbind the buffer from the
> GTT. This needs to only be performed if the buffer still resides in the
> GTT domain, and so we can skip some needless barriers otherwise.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 3c4577b..ed8d21a 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2526,15 +2526,15 @@ static void i915_gem_object_finish_gtt(struct drm_i915_gem_object *obj)
> {
> u32 old_write_domain, old_read_domains;
>
> - /* Act a barrier for all accesses through the GTT */
> - mb();
> -
> /* Force a pagefault for domain tracking on next user access */
> i915_gem_release_mmap(obj);
>
> if ((obj->base.read_domains & I915_GEM_DOMAIN_GTT) == 0)
> return;
>
> + /* Wait for any direct GTT access to complete */
> + mb();
> +
> old_read_domains = obj->base.read_domains;
> old_write_domain = obj->base.write_domain;
>
Yeah this looks like a better place to put it. You're trying to
serialize this against a subsequent fence or map operation?
Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>
--
Jesse Barnes, Intel Open Source Technology Center
